God is God Alone

Hear, O Israel: The Lord our God, the Lord is one. Deuteronomy 6:4

There is only one God. As Christians, we are supposed to worship only one God. Not one God plus something else. We are not permitted to pray to anything or anyone save the one true God. In fact, God explicitly forbids worship of anything or anyone but him.

You shall not make for yourself an image in the form of anything in heaven above or on the earth beneath or in the waters below. You shall not bow down to them or worship them; for I, the Lord your God, am a jealous God...

If you are a Christian and have accepted Jesus as your Savior, God is jealous of your worship. He does not accept prayer to something or someone other than himself. He does not want us to turn to idols or other places for our deliverance; he does not want us to think of anything or anyone as more important to us than he is. We are to have no other gods; only the one. 

So it might seem confusing at first that God is described as being three in one—God the Father, God the Son, and God the Holy Spirit. But it is important to remember that this is not three separate gods, but rather three parts of the same God. As I have said before, humans also have three parts—body, soul, spirit. But we are one person. God also has three parts—father, son, and Holy Spirit. But he is one God. And we worship him and him alone.